I never could figure this out. I just turn the touchpad off with, on my Samsung, Fn-F10 and use a wireless mouse. Someone else might be able to be more specific, but they will probably need information about what computer you are using.

The command hata_ph gave almost always works. The reason it didn't work for you is because the system thinks that this is a mouse and not a touchpad. You might wish to remember that if someone says something about "synaptics", "syndaemon", or "synclient", it won't work for this touchpad. I also assumed it would work. It's just an unusual combination that needs something different.

I think I did find something that will work: Hold down the blue "FN" key (it's next to your left "ctrl" key), press the left button on your touchpad, then release the FN and touchpad button. That should turn tap-to-click off.

If you do it again, it will turn tap-to-click back on.

Any operating system needs special software to do this with this keyboard/touchpad automatically, and I don't think that anyone's written that for Linux yet. But most people using this keyboard on Linux seem happy about it, so keep it if you like it. You will have to do FN+left-button each session, but that's not hard. If you just log out after this and someone else logs in, tap-to-click will still be off: FN+left-button again to turn it on. I don't know any other way to do it just for you, sorry.

Maybe someone will write software that will do this automatically for Linux. Maybe not.

Thank you very much for providing info about your system. If I didn't know you were using that particular keyboard, there's no way I could have answered. All I had to do was put "linux logitech k400 tap-to-click" in a search box and use some of what I know to read through the results.